Steroid Metabolism by the Immature Rat Testis

1974 ◽  
Vol 52 (9) ◽  
pp. 744-750 ◽  
Author(s):  
W. H. Moger ◽  
D. T. Armstrong
Keyword(s):  
Luteinizing Hormone ◽  
Male Rats ◽  
Steroid Metabolism ◽  
Immature Rat ◽  
Rat Testis ◽  
Immature Male ◽  
Immature Rats ◽  
Rapid Conversion

Treatment of hypophysectomized immature male rats with luteinizing hormone (LH) greatly increased the metabolism of both 4-[14C]progesterone and 4-[14C]testosterone by testicular homogenates. Prolactin, either alone or in combination with LH, did not influence the metabolism of either substrate. Progesterone was metabolized to 17α-hydroxyprogesterone, androstenedione, 5α-pregnan-3,20-dione, 3α-hydroxy-5α-pregnan-20-one, and 3β-hydroxy-5α-pregnan-20-one. Testosterone was metabolized to dihydrotestosterone and 5α-androstan-3α,17β-diol. On the basis of these observations it is suggested that LH stimulated the 5α-reductase(s) of the immature rat testis. Testis homogenates from immature rats with intact pituitaries were incubated with 4-[14C]3α-hydroxy-5α-pregnan-20-one. Rapid conversion to androsterone was observed, with the formation of a compound chromatographically identical with 3α, 17α-dihydroxy-5α-pregnan-20-one as an apparent intermediate. These findings demonstrate the ability of the rat testes to form androsterone from progesterone by a pathway that does not involve testosterone.

RADIOAUTOGRAPHIC STUDIES ON THE LOCALIZATION OF 125I-LABELLED HUMAN LUTEINIZING AND GROWTH HORMONE IN IMMATURE MALE RATS

1969 ◽  
Vol 43 (1) ◽  
pp. 105-111 ◽  
Author(s):  
D. M. DE KRETSER ◽  
K. J. CATT ◽  
H. G. BURGER ◽  
G. C. SMITH
Keyword(s):  
Growth Hormone ◽  
Adipose Tissue ◽  
Luteinizing Hormone ◽  
Human Growth Hormone ◽  
Light Microscope ◽  
Human Growth ◽  
Proximal Convoluted Tubule ◽  
Male Rats ◽  
Immature Male ◽  
Parenchymal Cells

SUMMARY Twenty-day-old male rats were injected intraperitoneally with either human luteinizing hormone (HLH) or human growth hormone (HGH) labelled with 125I. The localization of these hormones 1–2 hr. after injection was examined under the light microscope after radioautography. Major sites of localization of labelled LH were the interstitial cells of the testis and the proximal convoluted tubule of the kidney. Some hormone was also present in adipose tissue, hepatic parenchymal cells, the mesothelial lining of the peritoneum and underlying macrophages. HGH was localized principally in the proximal convoluted tubule of the kidney with some hormone present in liver, adipose tissue, and the suprarenal cortex.

REVERSAL BY ARGININE-VASOTOCIN OF THE EFFECTS OF PINEALECTOMY ON THE AMOUNT OF 5-HYDROXYTRYPTAMINE IN THE HYPOTHALAMUS AND THE CONCENTRATIONS OF LUTEINIZING HORMONE AND FOLLICLE-STIMULATING HORMONE IN THE PLASMA OF IMMATURE MALE RATS

1980 ◽  
Vol 84 (1) ◽  
pp. 159-161 ◽  
Author(s):  
S. PAVEL ◽  
NOEMI LUCA ◽  
MARIA CALB ◽  
R. GOLDSTEIN
Keyword(s):  
Luteinizing Hormone ◽  
Wistar Rats ◽  
Third Ventricle ◽  
Follicle Stimulating Hormone ◽  
Arginine Vasotocin ◽  
Male Rats ◽  
The Third ◽  
Immature Male ◽  
Receptor Sites ◽  
Male Wistar Rats

Pinealectomy in immature (25-day-old) male Wistar rats significantly decreased the content of 5-hydroxytryptamine (5-HT) in the hypothalamus and increased concentrations of plasma LH and FSH 3 days after surgery. Extremely small amounts (10−4 pg) of arginine-vasotocin (AVT) injected into the third ventricle (pineal recess) 5 min after pinealectomy completely prevented the decrease in the hypothalamic content of 5-HT and the increase in the concentration of LH and FSH in the plasma. It is suggested that AVT prevented the increase of plasma levels of LH and FSH after pinealectomy by increasing levels of 5-HT at postsynaptic receptor sites.

scholarly journals Characterization of the UDP-glucuronosyltransferase isoenzyme expressed in rat ovary and its regulation by gonadotropins

1998 ◽  
Vol 332 (1) ◽  
pp. 51-55 ◽  
Author(s):  
Luisa BECEDAS ◽  
Bo LUNDGREN ◽  
Joseph W. De PIERRE
Keyword(s):  
Luteinizing Hormone ◽  
Chorionic Gonadotropin ◽  
Follicle Stimulating Hormone ◽  
Immature Rat ◽  
Immature Rats ◽  
Serum Gonadotropin ◽  
Immunoreactive Band ◽  
Rat Ovary ◽  
Udp Glucuronosyltransferase

Earlier studies have demonstrated that phenol UDP-glucuronosyltransferase (UGT) activity is up-regulated by pregnant mare's serum gonadotropin (PMSG) in rat ovary, but not liver. This phenomenon was investigated in more detail in the present study. Ovaries and livers of immature rats, rats synchronized with respect to their preovulatory and corpus lutealphases by treatment with PMSG, and mature rats hyperstimulated with PMSG were compared. Under all of these conditions, only one immunoreactive band of UGT, shown to be phenol UGT, was detected in the rat ovary. The effects of oestradiol, progesterone and/or human chorionic gonadotropin (hCG) on the level of phenol UGT in immature rat ovary were also examined. Partial up-regulation was caused by progesterone or oestradiol, together with hCG, whereas progesterone or oestradiol alone had no up-regulating effect. Follicle-stimulating hormone also seemed to be required for the up-regulation in ovaries enriched in corpus luteum. The present findings demonstrate that progesterone is involved in the regulation of phenol UGT in rat ovary by gonadotropins. Regulation by both progesterone and oestradiol was dependent on induction of ovulation and steroidogenesis by luteinizing hormone.

ISOLATION AND CHARACTERIZATION OF INHIBIN FROM BULL SEMINAL PLASMA

1978 ◽  
Vol 87 (2) ◽  
pp. 434-448 ◽  
Author(s):  
S. Chari ◽  
S. Duraiswami ◽  
P. Franchimont
Keyword(s):  
Seminal Plasma ◽  
Gel Filtration ◽  
Male Rats ◽  
Acetone Powder ◽  
Alkaline Ph ◽  
Sodium Acetate Buffer ◽  
Immature Rat ◽  
Immature Male ◽  
Isolation And Characterization

ABSTRACT A simple, short procedure for the isolation of inhibin from bull seminal plasma has been described. Following conversion of the seminal plasma into acetone powder, it was subjected to gel filtration on Sephadex G-100 using 4 m urea—0.05 m sodium acetate buffer pH 4.0 as the eluent. Further purification of the active fraction was achieved by 'straight elution analysis' using CM-cellulose. The final preparation (Ux) has been shown to reduce the response of immature rat ovaries to human chorionic gonadotrophic hormone (HCG) stimulation in the bioassay system of Chari et al. (1976) and also been shown to suppress the immediate post-castration rise in serum gonadotrophin levels in immature male rats. Homogeneity of the isolated fraction has been assessed electrophoretically at different pH's above and below its isoelectric point. On the basis of gel filtration studies, electrophoresis and amino acid analysis, the molecular weight of Ux has been estimated to be 19 000 daltons. The electrophoretic behaviour of Ux at an alkaline pH has been discussed as a possible evidence for its existence as isohormones.

RESPONSE OF THE PITUITARY-TESTICULAR AXIS TO LUTEINIZING HORMONE-RELEASING HORMONE IN THE IMMATURE MALE RAT

1977 ◽  
Vol 84 (2) ◽  
pp. 254-267 ◽  
Author(s):  
H. Edward Grotjan ◽  
Donald C. Johnson
Keyword(s):  
Luteinizing Hormone ◽  
Control Level ◽  
Serum Testosterone ◽  
Male Rats ◽  
Male Rat ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Immature Male ◽  
Serum Lh ◽  
Lh Rh

ABSTRACT Follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone and androstenedione were measured by radioimmunoassays in the sera of immature male rats treated with luteinizing hormone-releasing hormone (LH-RH). A single dose of 10, 20, 40 or 80 ng of LH-RH produced a prompt increase in serum LH: significant changes in FSH were found only with the two larger doses. Serum testosterone increased to peak levels in 20 to 40 min and returned to control level by 120 min. Changes in androstenedione were temporally similar but smaller in magnitude. Four doses of 20 or 40 ng LH-RH given at 20 min intervals did not increase serum LH or testosterone concentrations above those found with a single injection; FSH was slightly higher after the fourth dose. However, 40 ng LH-RH given every 20 min for 2 h produced a dramatic increase in serum LH and FSH: serum and testicular androgens were also much higher during the second hour. A 2 h stimulation with 80 ng LH-RH given ip at 30 min intervals did not alter the response to the same treatment given 24 h later; i. e., neither the pituitary nor the gonad was primed by previous exposure to increased levels of LH-RH or gonadotrophins. These results suggest that a single pulse of LH-RH produces a predictable response in the animal, but multiple episodic stimuli produce variable responses: testes, on the other hand, produce androgens as long as gonadotrophins are available.

EFFECT OF SERUM GONADOTROPHIN ON DEHYDROGENASES OF THE CITRIC ACID CYCLE IN THE OVARY OF THE RAT

1963 ◽  
Vol 42 (4) ◽  
pp. 480-484 ◽  
Author(s):  
B. Eckstein ◽  
R. Landsberg
Keyword(s):  
Citric Acid ◽  
Citric Acid Cycle ◽  
Age Groups ◽  
Succinic Dehydrogenase ◽  
Immature Rat ◽  
Acid Cycle ◽  
Immature Rats ◽  
Rat Ovary

ABSTRACT The succinic, malic and isocitric dehydrogenases in the ovary of immature and mature, normal and serum gonadotrophin injected rats were examined. The Qo2 of these enzymes were markedly enhanced in the gonadotrophin injected rats of both age groups, except in the case of succinic dehydrogenase in the ovary of the immature rats, where a slight non-significant decrease was noted. It is concluded that in the mature rat ovary, gonadotrophin administration stimulates the activity of all the examined dehydrogenases of the citric acid cycle, whereas in the immature rat ovary, at least the isocitric- and malic dehydrogenases are thus stimulated.

Sign in / Sign up

Export Citation Format

Share Document