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From a flounder pituitary cDNA library, cDNA clones encoding a 28-kDa glycoprotein produced by the pars intermedia of the pituitary were isolated and characterized. Nucleotide sequencing demonstrated a precursor of the 28-kDa protein, which consisted of 231 amino acid residues, to be cleaved into a signal peptide (24 amino acids) and a mature protein (207 amino acids) containing one N-glycosylation site. By comparison of amino acid sequences, the 28-kDa protein was found to be distantly and similarly related to growth hormone and prolactin. Consequently, it was named somatolactin. Somatolactin mRNAs were specifically expressed as 1.2 and 1.8 kb poly(A)+ RNAs in flounder pituitary.

Crocetin is a natural carotenoid dicarboxylic acid that is found in the fruit of Gardenia jasminoides Ellis (Cape Jasmine) and in the stamen and pistil of Crocus sativus L. (saffron). It is used worldwide as an important spice, food colorant, and herbal medicine. In the current investigation, we have examined the cardiovascular effects of crocetin using stroke-prone spontaneously hypertensive rats (SHRSPs). Male SHRSPs (6 weeks old) were classified into three groups: a control group and two crocetin groups (25 and 50 mg/kg/day). The animals were given crocetin for 3 weeks. Body weights in each group were not significantly different during the treatment period, but the increase in systolic blood pressures observed with age was significantly moderated by crocetin. Thrombogenesis, assessed using a He-Ne laser technique in pial vessels, was significantly decreased. Antioxidant activity, assessed by measuring urinary 8-hydroxy-2'-deoxyguanosine levels, together with urinary nitric oxide (NO) metabolite levels, was increased significantly after treatment. Acetylcholine-induced vasodilation was measured using the aorta and indicated that endothelial function was significantly improved by crocetin. These results strongly suggest that the antihypertensive and antithrombotic effects of crocetin were related to an increase in bioavailable NO, possibly mediated by decreased inactivation of NO by reactive oxygen species.

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The amino acid sequence predicted from a rat liver cDNA library indicated that the precursor of b-AlaAT I (4-aminobutyrate aminotransferase, b-alanine±oxoglutarate aminotransferase) consists of a mature enzyme of 466 amino acid residues and a 34-amino acid terminal segment, with amino acids attributed to the leader peptide. However, the mass of b-AlaAT I from rat brain was larger than that from rat liver and kidney, as assessed by Western-blot analysis, mass spectroscopy and N-terminal sequencing. The mature form of b-AlaAT I from the brain had an ISQAAAK-peptide on the N-terminus of the liver mature b-AlaAT I. Brain b-AlaAT I was cleaved to liver b-AlaAT I when incubated with fresh mitochondrial extract from rat liver. These results imply that mature rat liver b-AlaAT I is proteolytically cleaved in two steps. The first cleavage of the motif XRX(5)XS is performed by a mitochondrial processing peptidase, yielding an intermediate-sized protein which is the mature brain b-AlaAT I. The second cleavage, which generates the mature liver b-AlaAT I, is also carried out by a mitochondrial endopeptidase. The second peptidase is active in liver but lacking in brain.Keywords: 4-aminobutyrate aminotransferase; GABA; mitochondrial processing peptidase; b-alanine aminotransferase; b-alanine. [4,5]. Malonate semialdehyde is converted into acetyl-CoA by methylmalonate semialdehyde dehydrogenase in the mitochondrial fraction [6,7].It is well established that 4-aminobutyrate (GABA) is a major inhibitory transmitter in many invertebrate systems and in the vertebrate central nervous system [8±10]. b-AlaAT I (GABA aminotransferase) together with succinate semialdehyde dehydrogenase and glutamate decarboxylase are the main components of the GABA shunt. b-AlaAT I in the brain is localized in the mitochondrial matrix [11] or in the inner mitochondrial membrane [12]. We proposed that the immunological and kinetic properties of b-AlaAT I from rat liver are similar to those of GABA aminotransferase from rat brain [13]. However, the N-terminal amino acid of rat liver b-AlaAT I is Val [13], while that of rat brain GABA aminotransferase has been identified as Ile by the dansyl method [14] and as Ser from the deduced amino acid sequence of the cDNA [15]. On the other hand, the N-terminal amino acid of liver and brain b-AlaAT I from pigs and humans is Ser [16,17]. This paper describes the N-terminal amino acid sequence and the molecular mass of mature b-AlaAT I in the liver and brain of rats. The N-terminal amino acid sequence of b-AlaAT I from rats is also compared with those from pigs [16] and humans [17].