Effects of growth hormone and gonadotropin on the insulin-like growth factor system in the porcine ovary.
The effects of growth hormone (GH) +/- pregnant mare's serum gonadotropin (PMSG) on levels of insulin-like growth factor (IGF)-I and -II and IGF binding protein (BP)-2 and -3 in serum and follicular fluid (FFI) and on the expression of their mRNA in the ovaries of prepubertal gilts were determined. Steroids in FFI were also quantified. In the first experiment, GH, given for either 20 or 40 days, caused a distinct (threefold, p < 0.05) increase in IGF-I in both serum and FFI with no change in the FFI:serum ratio (0.65). Effects of GH on IGF-II were opposite, with a drop in circulating and FFI levels (p < 0.05). In contrast to data for IGF-I, FFI levels were higher than those in serum for IGF-II (1.42, FFI:serum); IGF-II levels and the ratio fell after GH treatment. GH for either 20 days or 40 days increased serum IGBP-3 to 140% and 250% of control values while decreasing serum IGFBP-2 by 46% and 31%, respectively (p < 0.001). FFI IGFBP-3 was increased to a similar extent by GH (p < 0.005), but IGFBP-2 was not affected. Neither progesterone (P4) nor estradiol (E2) was affected by treatment with GH. However, androstenedione (A4) was decreased by 20-day and 40-day GH treatment relative to the respective controls (p < 0.05). In the second experiment, PMSG resulted in a modest (28%) increase in intrafollicular IGF-I (p < 0.06).(ABSTRACT TRUNCATED AT 250 WORDS)
Samaras
S E
SE
Department of Medicine, Milton S. Hershey Medical Center, Pennsylvania State University, Hershey 17033.
Hagen
D R
DR
Bryan
K A
KA
Mondschein
J S
JS
Canning
S F
SF
Hammond
J M
JM
D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D002850:Chromatography, Gel; D000431:Ethanol; D005260:Female; D015571:Follicular Fluid / Q000378:metabolism; D015870:Gene Expression; D006064:Gonadotropins, Equine / Q000494:pharmacology*; D013006:Growth Hormone / Q000494:pharmacology*; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007335:Insulin-Like Growth Factor II / Q000378:metabolism; D010053:Ovary / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D013002:Somatomedins / Q000235:genetics / Q000378:metabolism*; D013552:Swine
D002352:Carrier Proteins; D006064:Gonadotropins, Equine; D018969:Insulin-Like Growth Factor Binding Proteins; D012333:RNA, Messenger; D013002:Somatomedins; D000431:Ethanol; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D013006:Growth Hormone