The effect of maternal somatostatin administration from days 14 to 20 of gestation was examined. Fetal body growth was unchanged but brain cell DNA synthesis per gram of tissue decreased. Maternal serum levels of growth hormone and brain trophin were elevated following treatment conclusion. It was suggested that this was a rebound phenomenon and that short term blockade of pituitary growth hormone release during somatostatin treatment had impaired fetal brain cell DNA synthesis.

Barramundi (Lates calcarifer) is a teleost of the superorder Acanthopterygii. Barramundi IGF-I cDNA was cloned and the distribution of alternative transcripts in various barramundi tissues was investigated using rt-PCR and RPA. It was demonstrated that in barramundi tissues, IGF-I mRNAs were represented by two transcripts corresponding to the reported salmonid Ea-2 and Ea-4. The acute effect of GH on hepatic IGF-I mRNA levels was investigated. Seven hours after intraperitonal administration of either 6 micrograms of recombinant bream GH/g body weight or saline, no significant increase in the levels of either of the two transcripts could be observed. The presence of GH receptors in the barramundi liver was demonstrated in binding assays using recombinant bream GH and liver membrane preparations. An analysis of a barramundi IGF-I genomic sequence encompassing the three exons that encode the E domain suggested that the pattern of splice site utilization is determined by the degree of homology of the splicing signals to the consensus splice site sequences.