Expression of a bovine growth hormone transgene inhibits pregnant mare's serum gonadotropin-induced follicle maturation in prepuberal gilts.
Prepuberal gilts were injected with PMSG to determine whether expression of a bovine growth hormone (bGH) transgene inhibited preovulatory maturation of ovarian follicles. Seven transgenic (TG) gilts of line 3706, which expresses a mouse metallothionein-bGH transgene, and eight nontransgenic, control (C) gilts (128 to 147 d old) were injected with PMSG, 12.5 IU/kg BW, 72 h before necropsy. Surface ovarian follicles > or = 1 mm in diameter were counted, measured for diameter, and aspirated for fluid. Follicles were classified morphologically as healthy or atretic and those with follicular fluid estradiol-17 beta > or = 100 ng/mL were classified as estrogenactive (EA). The number of follicles per gilt was 64.3 +/- 6.1 (mean +/- SEM) and did not differ significantly between bGH-TG and C gilts. The PMSG treatment induced growth of large (> 5 mm) follicles in both bGH-TG and C gilts. However, compared with C gilts, bGH-TG gilts had fewer (P < .05) large follicles (5.9 +/- 1.5 vs 18.3 +/- 5.4), a lower proportion of EA large follicles (35 +/- 12.5 vs 69 +/- 13.2%), and in large follicles less (P < .05) estradiol-17 beta (86 +/- 17 vs 350 +/- 69 ng/mL) and androstenedione (300 +/- 33 vs 1,283 +/- 221 ng/mL). Follicular fluid progesterone and inhibin did not differ significantly between bGH-TG and C gilts. The incidence of atresia among small and medium follicles did not differ significantly between bGH-TG and C gilts.(ABSTRACT TRUNCATED AT 250 WORDS)
Guthrie
H D
HD
Germplasm and Gamete Physiology Laboratory, ARS, USDA, Beltsville, MD 20705.
Pursel
V G
VG
Bolt
D J
DJ
Cooper
B S
BS
D000735:Androstenedione / Q000032:analysis; D000818:Animals; D030801:Animals, Genetically Modified / Q000235:genetics / Q000502:physiology*; D004958:Estradiol / Q000032:analysis; D005260:Female; D005496:Follicular Atresia / Q000235:genetics; D015571:Follicular Fluid / Q000737:chemistry; D015870:Gene Expression; D006064:Gonadotropins, Equine / Q000494:pharmacology*; D013006:Growth Hormone / Q000235:genetics*; D007265:Inhibins / Q000032:analysis; D006080:Ovarian Follicle / Q000187:drug effects / Q000502:physiology*; D011374:Progesterone / Q000032:analysis; D013552:Swine / Q000235:genetics / Q000502:physiology*
D006064:Gonadotropins, Equine; D000735:Androstenedione; D011374:Progesterone; D004958:Estradiol; D007265:Inhibins; D013006:Growth Hormone