Decreased serum testosterone and free triiodothyronine levels in healthy middle-aged men indicate an age effect at the pituitary level

1995 ◽  
Vol 132 (6) ◽  
pp. 663-667 ◽  
Author(s):  
Eva Marie T Erfurth ◽  
Lars E Hagmar
Keyword(s):  
Luteinizing Hormone ◽  
Young Men ◽  
Serum Testosterone ◽  
Free Testosterone ◽  
Age Effect ◽  
Hormone Response ◽  
Middle Aged ◽  
Free Triiodothyronine ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone

Erfurth EMT, Hagmar LE. Decreased serum testosterone and free triidothyronine levels in healthy middle-aged men indicate an age effect at the pituitary level. Eur J Endocrinol 1995;132:663–7. ISSN 0804–4643 In an attempt to study further the age-specific influence on the hypothalamo-pituitary–gonadal axis as well as the hypothalamo–pituitary–thyroid axis, we have now investigated young and middle-aged men, considering possible confounding factors. Both serum total testosterone, free testosterone and the total ratio of testosterone to sex-hormone binding globulin were significantly lower among middle-aged men as compared with young men (p = 0.02, p = 0.002 and p = 0.0003, respectively). In accordance with these findings there was also a decrease in the luteinizing hormone response to gonadotrophin-releasing hormone in the middle-aged men (p= 0.02). Free testosterone was correlated significantly with the luteinizing hormone response (r = 0.32, p = 0.02). Serum free triiodothyronine was significantly higher among young men as compared with middle-aged men (p = 0.002) and the thyrotrophin-releasing hormone-stimulated thyrotrophin response was also higher in the young group compared with the middle-aged group. The present results may indicate that the age effect on serum levels of testosterone and free triidothyronine is mediated at the pituitary level. Eva Marie Erfurth, Dept. of Internal Medicine, University of Lund, S-221 85 Lund, Sweden

Somatostatin and Thyrotrophin-Releasing Hormone Response and Receptor Status of a Thyrotrophin-Secreting Pituitary Adenoma: Clinical and in vitro Studies

1989 ◽  
Vol 1 (5) ◽  
pp. 321-326 ◽  
Author(s):  
Andrew Levy ◽  
David J. A. Eckland ◽  
Alison M. Gurney ◽  
Jean-Claude Reubi ◽  
Rasikbala Doshi ◽  
...  
Keyword(s):  
Pituitary Adenoma ◽  
In Vitro Studies ◽  
Hormone Response ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Receptor Status

scholarly journals Growth hormone response to thyrotrophin releasing hormone in women with polycystic ovarian syndrome

1999 ◽  
Vol 14 (11) ◽  
pp. 2704-2708 ◽  
Author(s):  
Th. Kaltsas ◽  
N. Pontikides ◽  
G.E. Krassas ◽  
K. Seferiadis ◽  
D. Lolis ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Polycystic Ovarian Syndrome ◽  
Growth Hormone Response ◽  
Hormone Response ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Ovarian Syndrome

EFFECTS OF MATING AND INJECTION OF LUTEINIZING HORMONE RELEASING HORMONE ON SERUM LUTEINIZING HORMONE AND TESTOSTERONE CONCENTRATIONS IN RABBITS

1978 ◽  
Vol 76 (3) ◽  
pp. 417-425 ◽  
Author(s):  
C. A. BLAKE ◽  
PATRICIA K. BLAKE ◽  
NANCY K. THORNEYCROFT ◽  
I. H. THORNEYCROFT
Keyword(s):  
Luteinizing Hormone ◽  
Serum Testosterone ◽  
Serum Levels ◽  
Transient Increase ◽  
Marked Rise ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Serum Lh ◽  
Before And After ◽  
Lh Rh

The effects of coitus and injection of luteinizing hormone releasing hormone (LH-RH) on serum concentrations of LH, testosterone and dihydrotestosterone (17β-hydroxy-5α-androstan-3-one; DHT) were tested in male rabbits. Before experimentation, male and female rabbits were housed in individual cages in the same room. Male rabbits were then bled by cardiac puncture before and after placement with female rabbits or intravenous injection of LH-RH. Serum LH, testosterone and DHT were measured by radioimmunoassay. Sexual excitement (sniffing, chasing and mounting), with or without intromission, caused a marked rise in serum testosterone and DHT concentrations in only some of the bucks. These increases were accompanied or preceded by a small, transient increase in serum LH. In the rest of the bucks, sexual excitement with or without intromission had either no effect on serum levels of all three hormones, or only serum testosterone and DHT decreased during the collection period. Similar responses were measured in bucks which were housed in a room without does for 2–4 weeks before experimentation. Injection of 10, 30 or 100 ng or 50 μg LH-RH caused serum LH, testosterone and DHT to rise in all bucks tested, but the magnitude of the rises in serum testosterone and DHT were not related to the magnitude of the LH rise. In both mated and LH-RH-injected bucks, the rises in serum testosterone and DHT were greatest in animals with low initial testosterone and DHT values. Under the conditions of this study, the data suggest that: (1) serum testosterone and DHT rise in only some male rabbits after sexual excitement (with or without intromission), (2) the rises in serum testosterone and DHT are dependent on a small transient increase in serum LH and (3) sexual excitement is less likely to cause release of LH-RH in bucks with raised serum testosterone and DHT concentrations.

Stimulatory effect of thyrotrophin-releasing hormone (TRH) on the release of luteinizing hormone (LH) from rat anterior pituitary cells in vitro

1983 ◽  
Vol 61 (2) ◽  
pp. 186-189 ◽  
Author(s):  
Noboru Fujihara ◽  
Masataka Shiino
Keyword(s):  
Luteinizing Hormone ◽  
Anterior Pituitary ◽  
Pituitary Cells ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Anterior Pituitary Cells ◽  
Lh Release ◽  
Lh Rh

The effect of thyrotrophin-releasing hormone (TRH, 10−7 M) on luteinizing hormone (LH) release from rat anterior pituitary cells was examined using organ and primary cell culture. The addition of TRH to the culture medium resulted in a slightly enhanced release of LH from the cultured pituitary tissues. However, the amount of LH release stimulated by TRH was not greater than that produced by luteinizing hormone – releasing hormone (LH–RH, 10−7 M). Actinomycin D (2 × 10−5 M) and cycloheximide (10−4 M) had an inhibitory effect on the action of TRH on LH release. The inability of TRH to elicit gonadotrophin release from the anterior pituitary glands in vivo may partly be due to physiological inhibition of its action by other hypothalamic factor(s).

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