COLLAGEN SYNTHESIS, DEGRADATION AND STABILITY AS INFLUENCED BY STEROID HORMONES IN MALE LAMBS (TESTOSTERONE, RAMS, MEAT, GROWTH)
Abstract
Experiments were conducted to explore the relationship of testosterone (T), dihydrotestosterone (DHT) and estradiol-17(beta) (E2) with serum hydroxyproline (HP) concentrations and intramuscular collagen (IC) properties. In experiment I, 65 rams were assigned to treatment (12, 18, 24 and 30 wk) groups. Animals were bled at 30 min intervals via intrajugular catheter between 0800 and 1600 h beginning 48 h before slaughter. Serum T values greater than one standard above the mean were defined as secretory spikes. The longissimus (L), supraspinatus (SS) and infraspinatus (IS) were analyzed for intramuscular collagen (IC), soluble collagen (SC) and intramuscular collagen thermal shrinkage temperature. In experiment II, 48 rams were assigned to eight treatments: intact; castration; castration plus implantation of 1, 3 or 6 capsules of T or 1, 3 or 6 capsules of DHT. Blood was analyzed at 14-d intervals until slaughter at 56 d. Samples of L were analyzed as in experiment I. Experiment III utilized 50 rams assigned to five treatments: intact; castration; castration plus implantation of E2, DHT or E2 plus DHT. Blood and muscle samples were taken and analyzed as in experiment II. Rams had higher (P < .05) serum HP concentrations and higher (P < .01) percent IC than wethers. Serum HP concentration, percent IC and percent SC decreased (P < .01) while collagen Ts increased (P < .01) with age in all lambs. Secretory spike frequency in rams increased (P < .01) with age. Implantation of T, DHT and E2 restored serum HP concentration in proportion to the amount of hormone implanted. Concentration of T and E2, but not DHT, increased (P < .01) percent IC, particularly in the L. These data indicate that rams and T- or E2-implanted wethers accumulate and degrade more collagen than wethers. Further experiments were conducted to develop a method to study collagen synthesis in cultured fibroblasts and to investigate the influence of T, E2 and DHT in cell culture. Thin-layer separation of proline and hydroxyproline resulted in approximately 50% recoveries and data from steroid were inconclusive.
Degree
Ph.D.
Subject Area
Livestock
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