Somatostatin receptor 1–5; expression profiles during rat development

Figures & data

Table I. PCR primers.

Primer		Sequences
TBP	Forward	ACCCTTCACCAATGACTCCTATG
	Reverse	ATGATGACTGCAGCAAATCGC
PBG	Forward	CCTGGCATACAGTTTGAAATCAT
	Reverse	TTTCCCTAAAAACAACAGCAT
G6PDH	Forward	ATTGACCACTACCTGGGCAA
	Reverse	GAGATACACTTCAACACTTTGACCT
SSTR1	Forward	CAAGATGAAGACCGCAACC
	Reverse	CACGATGGGCAAGATAACC
SSTR2	Forward	GCTCGTGGAAAAGCAAGATGT
	Reverse	CCGTTGAGGTCAAAGGGAG
SSTR3	Forward	TGGCTGTGCTCTGGTGGTA
	Reverse	GGATTCAGTCAGCAGCCAACTAG
SSTR4	Forward	GGAAGCAGGTGGTGGTCAG
	Reverse	ATTTGCATTCGCAGGAAGTCT
SSTR5	Forward	CTGTCCTGCACAGAGACACG
	Reverse	CATTGGCGATGCTGAGC

Table II. Summarized protein expression of SSTR1–5 in major structures identified in rat embryos from day 10 to birth.

Structure	Embryonal day	SSTR1	SSTR2	SSTR3	SSTR4	SSTR5
Neural tube	10	+	+	++	+	++
	11	++	++	++	+	+
	12	+	–	+	++	++
Yolk sac	10	++	++	+	++	+
	11	+	+	+	+	+
	12	n.i.	n.i.	n.i.	n.i.	n.i.
Aorta	10	+	+	+	++	+
	11	+	++	+	+	+
	12	–	–	+	+	+
Skin	10	n.i.	n.i.	n.i.	n.i.	n.i.
	11	n.i.	n.i.	n.i.	n.i.	n.i.
	12	–	–	–	+	+
	14	+	++	+	++	++
	15	++	++	+	++	++
	17	++	++	+	++	++
	19	+	+	–	–	++
	Newborn	+	++	++	++	++
Heart	10	–	–	–	–	+
	11	++	–	++	+	+
	12	+	–	+	++	+
	14	+	+	+	+	+
	15	+	+	+	+	+
	17	+	+	–	+	+
Liver	14	+	+	+	+	+
	15	+	+	+	+	+
	17	–	+	+	+	+
	19	+	+	–	–	+
	Newborn	n.i.	n.i.	n.i.	n.i.	n.i.
Cartilage	14	–	+	+	–	+
	15	+	+	+	–	+
	17	++	++	–	+	+
	19	++	++	–	+	+
	Newborn	++	+	–	+	+
Retina	14	–	–	+	–	+
	15	–	+	+	–	+
	17	–	++	–	+	+
	19	++	++	–	–	+
	Newborn	n.i.	n.i.	n.i.	n.i.	n.i.
Lens	14	–	–	++	–	+
	15	+	–	++	+	++
	17	+	+	+	++	++
	19	–	+	–	–	+
	Newborn	n.i.	n.i.	n.i.	n.i.	n.i.
Muscle	14	n.i.	n.i.	n.i.	n.i.	n.i.
	15	+	+	++	–	++
	17	+	+	++	–	++
Diencephalon	14	+	+	+	++	++
	15	+	+	+	+	++
	17	++	+	+	–	+
Mesencephalon	14	+	+	+	++	++
	15	+	+	+	+	++
	17	n.i.	n.i.	n.i.	n.i.	n.i.
Rhomencephalon	14	+	+	+	++	++
	15	+	+	+	+	++
	17	n.i.	n.i.	n.i.	n.i.	n.i.

The distribution and intensity of SSTR staining were scored semi-quantitatively. The immunostainings are reported for SSTR1, SSTR2, SSTR3, SSTR4, and SSTR5 for all major structures in rat embryos.

+ weak positive staining; ++ clear positive staining; – not detected; n.i. tissue not investigated.

Figure 1. The immunohistochemical staining for SSTR subtypes. A: At embryonal day 11 (SSTR1, magnification 100×); B: day 15 (SSTR2, magnification 16×); and C: day 17 (SSTR5, magnification 16×) in rat embryos. Positive staining by SSTR antibodies is highlighted by red colour. D–G: Structures in rat embryos from day 15 to birth (magnification 200×). D: positive staining of SSTR3 in the lens at day 15. E: The outer part of the skin expresses SSTR4 at day 15; F: part of the eye is positive for SSTR1 at day 19; and G: the outer part of the skin is immunostained for SSTR5 in the newborn.

Figure 2. Expression of SSTR mRNAs in the embryonic rat pancreas amplified using real-time PCR. A: SSTR1; B: SSTR2; C: SSTR3; D: SSTR4; E: SSTR5. Data are given as mean relative expression (2-Δ(cpssts-cpTBP)) of embryonal pancreases from the same day.

Figure 3. Expression of SSTR mRNAs of entire rat embryos amplified using real-time PCR. A: SSTR1; B: SSTR2; C: SSTR3; D: SSTR4; E): SSTR5. Embryos pooled from one pregnant rat (n = 11) were considered as one observation.

Table III. Quantitative analysis of the expression of SSTRs in β-cells, α-cells, δ-cells, or PP-cells in the fetal rat pancreas from day 19, 21 and in the newborn. Percentages are proportion of cells in which immunofluorescence was detected.

Embryonal day ^a	SSTR1 (%)	SSTR2 (%)	SSTR3 (%)	SSTR4 (%)	SSTR5 (%)
β-cells
E19	80	2	15	0	0
E21	5	2	30	67	0
Newborn	85	2	2	65	0
Adult ^b	50	40	40	35	60
α-cells
E19	50	75	2	5	80
E21	5	65	15	10	15
Newborn	5	60	5	30	40
Adult ^b	40	80	20	20	85
δ-cells
E19	35	55	5	0	20
E21	15	18	45	0	5
Newborn	10	60	75	10	15
Adult ^b	60	70	70	80	40
PP-cells
E19	60	85	100	20	30
E21	20	20	40	15	35
Newborn	80	30	35	20	15
Adult ^b	30	15	15	15	20

^a Developmental stage of pancreatic specimens investigated.

^b For comparative purposes observations from a previous study (30) on adult rat pancreases have been included.

Ludvigsen E, Olsson R, Stridsberg M, Janson ET, Sandler S. Expression and distribution of somatostatin receptor subtypes in the pancreatic islets of mice and rats. J Histochem Cytochem. 2004;52:391–400.

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