Read by QxMD icon Read


D E Kime, A P Scott
Testes from spermiating goldfish were incubated with [(3)H]17-hydroxyprogesterone. The major products in the unconjugated fraction were identified as androstenedione, androstenetrione, 11-β-hydroxyandrostenedione, 11-ketotestosterone, 17,20α-dihydroxy-4-pregnen-3-one (17,20αP) and 11-deoxycortisol. Testosterone was present predominantly in the glucuronide fraction, but yields were low (1-3%). The major components of the sulfate fraction were 17,20αP and 11-deoxycortisol. The identification of cortisone in low yield (< 2...
July 1993: Fish Physiology and Biochemistry
J E Cavaco, C Vilrokx, V L Trudeau, R W Schulz, H J Goos
The effects of sex steroids on spermatogenesis and testicular androgen secretion were studied in juvenile (spermatogonia present in testes) African catfish. Fish were implanted with Silastic pellets containing 11-ketotestosterone (KT), 11beta-hydroxyandrostenedione (OHA), androstenetrione (OA), androstenedione (A), testosterone (T), 5alpha-dihydrotestosterone (DHT), or estradiol-17beta (E2). Control groups received steroid-free pellets. Two weeks later, testis tissue fragments were incubated with African catfish luteinizing hormone (LH) and the amount of OHA secreted in vitro (the main androgen produced by African catfish testes) was quantified...
December 1998: American Journal of Physiology
M N Khan, R L Renaud, J F Leatherland
This study examines the ability of Arctic charr (Salvelinus alpinus) embryos to metabolize tritiated androstenedione (A4), testosterone (T), 17 beta-estradiol (E2), and estrone (E1) in vitro; the metabolic products were separated by HPLC. A4 was poorly metabolized, with 48 to 64% of the substrate remaining even after 24 hr of incubation. The major metabolites of A4 metabolism are E1 and some other unidentified metabolites. T was mostly converted to A4, along with some reduced steroids, but E2 was a minor metabolite...
July 1997: General and Comparative Endocrinology
D E Kime, P B Singh
Testicular and ovarian fragments of Carassius auratus, taken during the reproductively active prespawning phase (June) of its annual reproductive cycle, were incubated with different concentrations (0 mg/ml, 0 ppm; 0.001 mg/ml, 1 ppm; 0.01 mg/ml, 10 ppm; and 0.02 mg/ml, 20 ppm) of gamma-hexachlorocyclohexane (gamma-HCH) in the presence of either exogenous precursor [3H]-17-hydroxyprogesterone ([3H]17-P) or carp hypophyseal homogenate. The free (unconjugated) and conjugated metabolites (glucuronides and sulfates) of [3H]-17-P [androstenedione (AD), androstenetrione, 17-hydroxyprogesterone, testosterone (T), 11-deoxycortisol (S), 17, 20alpha-dihydroxy-4-pregnen-3-one (17,20alphaP), 17, 20beta-dihydroxy-4-pregnen-3-one (17,20betaP), 7alpha-pregnanetetrols (7alpha-P), and other polar metabolites] were separated by thin-layer chromatography and high-performance liquid chromatography...
July 1996: Ecotoxicology and Environmental Safety
M Ebrahimi, P B Singh, D E Kime
The effect of incubation time and substrate concentration on the in vitro metabolism of 17-hydroxyprogesterone by testes of the roach has been examined. There was a shift from synthesis of the 11-oxygenated androgens, 11-ketotestosterone, and androstenetrione at low substrate concentration to 17,20 alpha-dihydroxy-4-pregnen-3-one (17,20 alpha P) at high substrate. Glucuronides and sulfates were of significant importance only at low substrate and long incubation times. There was a shift from 17,20 beta-dihydroxy-4-pregnen-3-one to 17,20 alpha P with increased substrate...
December 1995: General and Comparative Endocrinology
M A Abdullah, D E Kime
Goldfish testes were incubated with [3H]17-hydroxyprogesterone in the presence of 0 to 100 micrograms/ml of unlabeled substrate and metabolites examined by thin-layer and high performance liquid chromatography. Conjugated steroids, predominantly sulfates, accounted for 50% of recovered activity with radiolabeled substrate alone, but percentage yields decreased to very low levels with substrate concentrations of 1 micrograms/ml and above. The 11-oxygenated androgens, androstenetrione and 11-ketotestosterone, were the major products with 0 to 0...
October 1994: General and Comparative Endocrinology
T Leitz, R Reinboth
Testicular tissues of the Siamese fighting fish were incubated with [14C]pregnenolone for 10, 20, 30, 50, 80, and 120 min, and with [14C]progesterone, [14C]11 beta-hydroxyandrostenedione, [14C]11 beta-hydroxytestosterone, and [14C]androstenetrione for 120 min. 11-Ketotestosterone was the main metabolite in all 120-min incubations. No 11-oxygenated C21 steroids were found as metabolites of either pregnenolone or progesterone. The biosynthesis of 11-ketotestosterone proceeded through both the delta 5- and the delta 4- pathways as judged from the shape of the yield-time curves of the metabolites of pregnenolone...
April 1987: General and Comparative Endocrinology
R Schulz, V Blüm
1. The secretion of five androgens was quantified from trout testes under GTH-stimulation in vitro before and after the onset of milt production, and a general increase of basal and GTH stimulated androgen secretion was recorded during this period. 2. 11-Ketotestosterone, testosterone, and in spermiating males, 11 beta-hydroxytestosterone as well showed GTH dependent concentration increases, while androstenetrione and 11 beta-hydroxyandrostendione were found in highly variable amounts. 3. 17 beta-Hydroxyandrogen glucuronides in the medium (with the exception of testosterone) and tissue androgens were by far exceeded by the free androgens in the medium...
1987: Comparative Biochemistry and Physiology. A, Comparative Physiology
P A Mason, R Fraser
A method for determining the plasma concentrations of six major corticosteroids, aldosterone, 18-hydroxy-11-deoxycorticosterone (18-OH-DOC), corticosterone, deoxycorticosterone (DOC), cortisol and 11-deoxycortisol using gas-liquid chromatography with electron capture detection is described. Esterification of suitable derivatives of these compounds with heptafluorobutyric anhydride (HFB) allowed detection of quantitities of steroid, ranging from 0-3 pg for androstenetrione HFB (from cortisol) to 2-3 pg for corticosterone HFB...
February 1975: Journal of Endocrinology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"