| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Luteinizing hormone (LH) and testosterone were measured in the peripheral plasma of two bulls by radioimmunoassay and competitive protein binding techniques. Samples were collected from an indwelling jugular catheter once an hour for 24 h, and then at more frequent intervals after a number of experimental procedures.
Each bull showed its own characteristic pattern of cyclic LH changes, with 5–10 peaks during 24 h that were apparently unrelated to daylight, feeding or sleep. Each LH peak was associated with a testosterone peak; the LH concentrations ranged from 5 to 50 ng/ml, and those of testosterone from 2 to 20 ng/ml.
Sexual stimulation, such as the sight of a cow, or 'teasing', or on one occasion the act of ejaculation itself, caused an immediate release of a large amount of LH. If the testosterone levels were low at the time, the LH peak was followed by a testosterone peak. But when the testosterone levels were high at the time of LH discharge, the testis seemed to be unable to respond any further. An intravenous injection of 500 i.u. human chorionic gonadotrophin was associated with LH release and caused the testosterone levels to rise to maximal values of 22 ng/ml within 1
h.
It is concluded that the cyclical pattern of LH release is due to some inherent central rhythm, and that each transient LH peak results in transient maximal stimulation of testicular testosterone secretion.
This article has been cited by other articles:
|
|
 |
|
  D B B P Paris, D A Taggart, G Shaw, P D Temple-Smith, and M B Renfree Changes in semen quality and morphology of the reproductive tract of the male tammar wallaby parallel seasonal breeding activity in the female Reproduction, September 1, 2005; 130(3): 367 - 378. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Foresta, P. Bordon, M. Rossato, R. Mioni, and J. D. Veldhuis Specific Linkages Among Luteinizing Hormone, Follicle-Stimulating Hormone, and Testosterone Release in the Peripheral Blood and Human Spermatic Vein: Evidence for Both Positive (Feed-Forward) and Negative (Feedback) Within-Axis Regulation J. Clin. Endocrinol. Metab., September 1, 1997; 82(9): 3040 - 3046. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. D. Zwart, A. Iranmanesh, and J. D. Veldhuis Disparate Serum Free Testosterone Concentrations and Degrees of Hypothalamo-Pituitary-Luteinizing Hormone Suppression Are Achieved by Continuous Versus Pulsatile Intravenous Androgen Replacement in Men: A Clinical Experimental Model of Ketoconazole-Induced Reversible Hypoandrogenemia with Controlled Testosterone Add-Back J. Clin. Endocrinol. Metab., July 1, 1997; 82(7): 2062 - 2069. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Graham and C Desjardins Classical conditioning: induction of luteinizing hormone and testosterone secretion in anticipation of sexual activity Science, November 28, 1980; 210(4473): 1039 - 1041. [Abstract] [PDF]
|
|
|
|
|
|
A Coquelin and F. Bronson Release of luteinizing hormone in male mice during exposure to females: habituation of the response Science, November 30, 1979; 206(4422): 1099 - 1101. [Abstract] [PDF]
|
|
|
|
|
|
P. Belchetz, T. Plant, Y Nakai, E. Keogh, and E Knobil Hypophysial responses to continuous and intermittent delivery of hypopthalamic gonadotropin-releasing hormone Science, November 10, 1978; 202(4368): 631 - 633. [Abstract] [PDF]
|
|
|
|
|
|
F Macrides, A Bartke, and S Dalterio Strange females increase plasma testosterone levels in male mice Science, September 26, 1975; 189(4208): 1104 - 1106. [Abstract] [PDF]
|
|
|
|
|
|
R. M. Rose, T. P. Gordon, and I. S. Bernstein Plasma Testosterone Levels in the Male Rhesus: Influences of Sexual and Social Stimuli Science, November 10, 1972; 178(4061): 643 - 645. [Abstract] [PDF]
|
|
| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
